Systematics Section / ASPT
Gilbert, Larry , Steele, Roxi , Jansen, Robert K. .
Identifying Informative Chloroplast Markers for Examining Phylogenetic Relationships Within Psiguria (Cucurbitaceae).
INTERGENIC spacers and introns of chloroplast DNA are commonly used as markers in phylogenetic studies focusing on species-level relationships in plants. It has become increasingly apparent that in order to obtain a useful number of informative characters at this low taxonomic level, a large number of nucleotide bases and, therefore, a great many regions must be investigated for infrageneric variation. Although several research efforts have been conducted to find noncoding regions that reliably show variation across all angiosperms, recent studies have revealed that the resulting markers do not contain consistent variability among families. Consequently, discovering informative markers is still a tedious process involving an exhaustive search through the genome. As part of my current project in which I am writing a monograph of the Neotropical genus Psiguria (Cucurbitaceae), I will include a phylogenetic tree based on morphological characters in combination with trees based on multiple genetic markers representing nuclear, mitochondrial, and chloroplast DNA. Toward this end, I selected 25 chloroplast noncoding regions to examine based on a consensus of results in the literature. These are: trnC-rpoB, ycf6-trnC, psbM-ycf6, psbD-trnT, trnT-trnE, trnE-trnD, trnD-psbM, trnfM-psbZ, trnS-trnG2S, trnG2G-trnG, rpL32-ndhF, trnL-rpL32, trnL-trnT, 3ítrnK-matK, trnQ-rps16, trnV-ndhC, petB-psbH, petD-petB, rps3-rpL16, ycf1-rps15, petL-psbE, psbJ-petA and the introns of rpL16, rps16, and ndhA. For this preliminary analysis, in order to maximize the opportunity for finding variation within the genus, I sequenced these regions in four representative species from various morphological characteristics and geographic areas. These are: Psiguria warscewiczii, P. bignoniacea, P. umbrosa, and one species in the sister genus Gurania costaricensis. Comparisons of noncoding chloroplast regions should provide valuable data for phylogenetic investigations of Psigura. These results also have the potential to provide useful information for low-level taxonomic studies in other members of Cucurbitaceae.
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Systematics and Biogeography of Psiguria (Cucurbitaceae)
1 - University of Texas Austin, Section of Integrative Biology, 1 University Station, C0930, Austin, Texas, 78712, USA
2 - University of Texas Austin, Plant Biology Graduate Program, 1 University Station A6720, Austin, Texas, 78712, USA
3 - University of Texas Austin, Section of Integrative Biology, 1 University Station, A6700, Austin, Texas, 78712-7640, USA
Presentation Type: Poster:Posters for Sections
Location: Auditorium/Bell Memorial Union
Date: Tuesday, August 1st, 2006
Time: 12:30 PM